The molecular biology of immunologically functional cells is being examined through analysis of key events during the immune response. A. Studies are being performed to examine effects of cytokine-mediated signals leading to induction of the perforin gene in CD8+ T-cells and Natura; Killer cells using a variety of transcriptional analysis techniques, including CAT reporter gene analysis of promoter truncations, nuclear run-on assay, and Northern blot analysis. Specific regulatory regions shall be examined by in vivo footprinting and electrophoretic mobility shift assay to determine transcription factor-DNA interactions. The significance of these studies lies in the identification of DNA regulatory regions and the interacting proteins responsible for specific- signal induction of transcription of immune function genes. B. The transcriptional response of immuno-modulatory cytokine genes during the immune response is being studied in selected immune cells and in two models of immune function: allogeneic skin graft rejection T-cell and macrophage mediated) and passive cutaneous anaphylaxis (IgE and mast cell mediated). Changes in the steady state transcription levels of a variety of growth factor- and chemotactic-type cytokine genes shall be determined using a semi-quantitative polymerase chain reaction. These studies shall determine the temporal appearance and relative levels of specific cytokine mRNAs and their sources. C. Recent progress. We found that HIV glycoprotein 120 stimulated the secretion of endothelin-1 and TNF-alpha from macrophages in a concentration-dependent manner and that circulating monocytes in HIV- infected individuals showed enhanced expression of endothelin-1. Cerebral macrophages in patients with HIV-encephalopathy were strongly positive for endothelin, suggesting that monocytic endothelins may mediate alterations in cerebral perfusion associated with AIDS dementia complex.